PCB Design Review: DPI-LVDS Sony Vaio LCD Devboard

March 12, 2024 by 12 Comments

Ordering a PCB with mistakes sucks. We should help each other avoid such mistakes – especially newcomers. One of the best ways to avoid these mistakes, especially if it’s your first one, is to get a few other people to look at it. You deserve to get a PCB that is as functional and as helpful as humanly possible, so that you can be happy with your project, and feel ever so slightly more confident in yourself in whatever you shall set out to do next.

At the end of last year, I put out a call for design review submissions, and we’ve received enough projects to make me feel overwhelmed for a bit. A design review has always felt like a personal thing, and here we are doing them in public. But in that sense, we hope that everyone can learn from them, and we hope to push forward a healthy review culture.

What’s more, these articles won’t just be design review. Every project I’m highlighting is worthy of a Hackaday feature just on its own, so tune in and learn more about them!

Today’s Contestant

For this example, I will be walking through a review I’ve already given someone with a pretty cool board, for a pretty cool project I’ve already shown you. Remember the Sony Vaio remake project? A fair bit of people have reached out to me afterwards, and one of them, [Exentio] also had the same Sony Vaio rebuild idea in mind. We started chatting, and he decided to tackle one of the project’s milestones, and perhaps the most crucial one – adapting the LCD.

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This Piano Does Not Exist

March 12, 2024 by 9 Comments

A couple of decades ago one of *the* smartphone accessories to have was a Bluetooth keyboard which projected the keymap onto a table surface where letters could be typed in a virtual space. If we’re honest, we remember them as not being very good. But that hasn’t stopped the idea from resurfacing from time to time.

We’re reminded of it by [Mayuresh1611]’s paper piano, in which a virtual piano keyboard is watched over by a webcam to detect the player’s fingers such that the correct note from a range of MP3 files is delivered.

The README is frustratingly light on details other than setup, but a dive into the requirements reveals OpenCV as expected, and TensorFlow. It seems there’s a training step before a would-be virtual virtuoso can tinkle on the non-existent ivories, but the demo shows that there’s something playable in there. We like the idea, and wonder whether it could also be applied to other instruments such as percussion. A table as a drum kit would surely be just as much fun.

This certainly isn’t the first touch piano we’ve featured, but we think it may be the only one using OpenCV. A previous one used more conventional capacitive sensors.

Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Pocket Cyberdeck

March 12, 2024 by 10 Comments

When you find something you love doing, you want to do it everywhere, all the time. Such is the case with [jefmer] and programming. The trouble is, there is not a single laptop or tablet out there that really deals well with direct sunlight. So, what’s a hacker to do during the day? Stay indoors and suffer?

Image by [jefmer] via Hackaday.IO
The answer is a project like Pocket Pad. This purpose-built PDA uses a Nice! Nano and a pair of two very low-power ST7302-driven monochrome displays. They have no backlight, but they update much faster than e-paper displays. According to [jefmer], the brighter the ambient light, the more readable the displays become. What more could you want? (Besides a backlight?)

The miniature PocketType 40% is a little small for touch typing, but facilitates thumbs well. [jefmer] added those nice vinyl transfer legends and sealed them with clear nail polish.

All of the software including the keyboard scanner is written in Espruino, which is an implementation of JavaScript that targets embedded devices. Since it’s an interpreted language, [jefmer] can both write and execute programs directly on the Pocket Pad, using the bottom screen for the REPL. I’d sure like to have one of these in my pocket!
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Unusual Port Combines DisplayPort And HDMI

March 12, 2024 by 22 Comments

Everyone knows you can’t plug an HDMI cable into a DisplayPort… port, and yet a recent video from [Jon Bringus] challenges that seemingly obvious assumption. The hardware in question is a variant of the 2013-era Xi3 X7A mini PC, code-named ‘Piston’ and also known as a ‘Steambox’, from back when that was still something that Valve was working on. Although the physical format here is definitely quaint, it might be implementing DisplayPort Dual-Mode (DP++), which was introduced around the same time.

With DP++ the DP port can detect when a DVI or HDMI adapter is connected and then transmit DVI/HDMI TMDS signals rather than DP signals. Since DP and HDMI/DVI use a different signaling scheme, normally an active adapter would be required. One disadvantage of DP++ is that the HDMI signal will be limited to e.g. 1920×1080 @ 120 Hz and 4K only at 30 Hz.

Normally a DP++ port is marked as such, and requires an adapter that works with the DP++ port. What Xi3 did in this case to make regular DP and HDMI connectors work seems to be somewhat of a mystery, with any information on this type of port being rather scarce. [Jon] thinks he may have found the part itself listed on Mouser, but isn’t completely sure.

Feel free to leave your thoughts and any information you have on this oddity in the comments.

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Stressless Shortwave Reviewed

March 12, 2024 by 17 Comments

[Dan Robinson] picked up a shortwave receiver known as the “stressless” receiver kit. We aren’t sure if the stress is from building a more complicated kit or operating a more complicated receiver. Either way, it is an attractive kit that looks easy to build.

Presumably to reduce stress, the VFO and receiver boards are already built, so assembly is just a few hours connecting large components and boards. As kits go, this is a fairly simple one. We were surprised to read that the supplier says you can’t upgrade the firmware. We, of course, wonder if that’s true.

For technical specs, the receiver is AM only and can operate from 100 kHz to 30 MHz. It uses a double conversion with intermediate frequencies of 21.4 MHz and 455 kHz. There’s a BNC connector on the back, and the radio requires 11 to 15V on the input. Apparently, the frequency generator inside is an SI5351. The sensitivity and selectivity numbers look very good for an AM radio.

We were surprised to see the radio didn’t have provisions for SSB since AM-only makes it not as useful for hams or others interested in non-broadcast transmissions. If we are doing our conversions correctly, the kit is fairly pricey, too, especially considering that it is AM only.

Still, we like that you could easily assemble a nice-looking radio kit. We were interested in hearing it perform, and [Dan’s] video lets us virtually try it out without the effort. We’ve seen the SI5351 on a carrier if you want to roll your own. Come to think of it, we’ve seen several.

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A 555-Shaped Discrete Component 555

March 11, 2024 by 2 Comments

While the “should have used a 555” meme is strong around these parts, we absolutely agree with [Kelvin Brammer]’s decision to make this 555-shaped plug-in replacement for the 555 timer chip using discrete parts, rather than just a boring old chip.

As [Kelvin] relates, this project started a while back as an attempt to both learn EDA and teach students about the inner workings of the venerable timer chip. The result was a 555-equivalent circuit on a through-hole PCB, with the components nicely laid out into the IC’s functional blocks. As a bonus, the PCB was attached to an 8-pin header which could be plugged right in as a direct replacement for the chip.

Fast forward a few years, and [Kelvin] needed to learn yet another EDA package; what better way than to repeat the 555 project? It was also a good time to step into SMD design, as well as add a little zazzle. While the updated circuit isn’t as illustrative of the internal arrangement of the 555, the visual celebration of the “triple nickel” is more than worth it. And, just like the earlier version, this one has a header so you can just plug and chug — with style.

Want to know how the 555 came to be? We’ve covered that. You can also look at some basic 555 circuits to put your 555-shaped 555 to work. We’ve even seen a vacuum tube 555 if that’s more your thing.

3D Imaging For Natural Science — For Free

March 11, 2024 by 4 Comments

It isn’t that unusual for a home lab to have a microscope, but wouldn’t it be cool to have a CT scanner? Well, you probably won’t anytime soon, but if you are interested in scans of vertebrates — you know, animals with backbones — a group of museums have you covered.

The oVert project is scanning 20,000 specimens and making the results available to everyone. This should be a boon to educators and might even be useful for 3D printing animal forms. Check out the video about the project below.

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